Valve and piston operative means for a circuit breaker

ABSTRACT

A device comprising an operating piston disposed at one end of an operating rod for operating a circuit breaker, a cylinder for guiding the operating piston in its sliding movement, a circuit making means adapted to provide a force for causing the operating rod to bring the circuit breaker to a circuit making position, a hook means adapted to be brought into engagement with the operating rod to maintain the circuit breaker in a circuit breaking position when instructions to break the circuit are given and released from engagement with the operating rod when instructions to make the circuit are given, a fluid introducing valve means for supplying an operating medium to the operating piston to move the same in a circuit breaking direction when instructions to break the circuit are given, and communication ports formed in a side wall of the cylinder to discharge therethrough from the cylinder to a lower pressure section the operating medium acting on the operating piston at least at the terminating stages of the circuit breaking operation, whereby the operating piston can be moved at fill speed. The fluid introducing valve means includes a fluid introducing valve disposed in the proximity of the operating piston and adapted to move toward the operating piston when brought to an open position, with its back being exposed to the operating medium at all times. By this arrangement, the device is capable of operating the circuit breaker at high speed even if the circuit breaker is under a high load and it has a large contact parting distance.

United States Patent 11 1 Hirasawa et al.

1 1 Sept. 23, 1975 VALVE AND PISTON OPERATIVE MEANS FOR A CIRCUIT BREAKER [75] Inventors: Kunio Hirasawa; Seizo Nakano,

both of Hitachi, Japan [73] Assignee: Hitachi, Ltd., Japan [22] Filed: Nov. 13, 1973 [21] Appl. No.: 415,328

200/82 R, 82 B, 82 C, 83 Q, 306, 320, 323325, 337, 290, 153 SC [56] References Cited UNITED STATES PATENTS 2,970,193 1/1961 Gratzmuller 200/82 B 2,972,337 2/1961 Coggeshall 200/82 R 3,062,934 11/1962 Nijland 1 200/82 R 3,334,202 8/1967 Tognella 200/82 3,519,022 7/1970 Chung 1 251/30 3,674,955 7/1972 Peek 200/82 B 3,698,682 10/1972 Berning 251/30 Primary Examiner-Gerald P. Tolin Attorney, Agent, or Firm-Craig & Antonelli IIHF "il// 1 1 ABSTRACT A device comprising an operating piston disposed at one end of an operating rod for operating a circuit breaker, a cylinder for guiding the operating piston in its sliding movement, a circuit making means adapted to provide a force for causing the operating rod to bring the circuit breaker to a circuit making position, a hook means adapted to be brought into engagement with the operating rod to maintain the circuit breaker in a circuit breaking position when instructions to break the circuit are given and released from engagement with the operating rod when instructions to make the circuit are given, a fluid introducing valve means for supplying an operating medium to the operating piston to move the same in a circuit breaking direction when instructions to break the circuit are given, and communication ports formed in a side wall of the cylinder to discharge therethrough from the cylinder to a lower pressure section the operating medium acting on the operating piston at least at the terminating stages of the circuit breaking operation, whereby the operating piston can be moved at fill speed. The fluid introducing valve means includes a fluid introducing valve disposed in the proximity of the operating piston and adapted to move toward the operating piston when brought to an open position, with its back being exposed to the operating medium at all times. By this arrangement, the device is capable of operating the circuit breaker at high speed even if the circuit breaker is under a high load and it has a large contact parting distance,

7 Claims, 5 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of4 3,908,106

US Patent Sept. 23,1975 Sheet 2 of4 3,908,106

FIG. 2

w M A0 w a 5 E: m 9 2 US Patent Sept. 23,1975 Sheet 3 of4 3,908,106

VALVE AND PISTON OPERATIVE MEANS FOR A CIRCUIT BREAKER BACKGROUND OF THE INVENTION This invention relates to circuit breaker operating devices. and more particularly it is concerned with a circuit breaker operating device capable of operating at high speed a circuit breaker which is under a high load and which has a large contact parting distance.

In recent years, an increasing demand for electric power has made it necessary to establish a high-power transmission network. If there is any accident in the high-power transmission network, service interruption will occur over a wide area. Thus, in order to minimize the effects of the accident, circuit breakers are required to possess capabilities to break the circuit at high speed.

Operation of circuit breakers at high speed requires operation of circuit breaker operating devices at high speed.

Circuit breakers used nowadays will be first explained with reference to a gas circuit breaker of the buffer type. The circuit breaker of this type operates such that an arch extinguishihg gas is compressed simultaneously as the contacts are moved apart from each other a large distance to produce an arc extinguishing gas of high pressure which is blown against an are produced between the contacts to extinguish the are. A force of high magnitude is required to operate such circuit breaker. A piston and a cylinder used for compressing the arc extinguishihg gas must have a large length because the piston must move a large distance to compress the gas. and the contacts must move away from each other a large distance.

Proposals have hitherto been made to use, to operate at high speed circuit breakers which are under a high load and which have a large contact parting distance, e.g. gas circuit breakers of the buffer type, circuit breaker operating devices of various types which rely on compressed air for actuating an operating piston. These circuit breaker operating devices have the disadvantage of not being able to continuously operate the circuit breaker at high speed in a short time interval. This stems from the fact that if stress is laid on bringing the circuit breaker to its circuit breaking position at high speed it becomes impossible to bring the circuit breaker to its circuit making position again at high speed from its circuit breaking position. Stated differently, means for bringing the circuit breaker to its circuit breaking position and means for bringing it back to its circuit making position are contradictory to each other in operation. This fact will be explained more in detail hereinafter.

Generally, in order to operate at high speed a piston which is adapted to be actuated by the pressure of compressed air, the initial volume of the space on the pressure receiving side of the piston should be minimized. This is because of a certain finite time elapses before the pressure of compressed air acts on the piston and the smaller the initial volume of the space, the shorter is the time.

On the other hand, the final volume of the space formed on the pressure receiving side of the piston is equal to the sum of the aforementined initial volume and the volume obtained by multiplying the pressure receiving area by the contact parting distance. Thus, if it is required to increase the speed with which the piston is operated. the final volume will become inordinately great in value as compared with the initial volume. In some cases. the latter is as much as one hundred times as great as the former. In order to restore the piston to a position in which the circuit breaker is brought to its circuit making position, it is required to vent to atmosphere the compressed air which maintains the piston in a position in which it keeps the circuit breaker in its circuit breaking position. It is a time consuming operation to vent the compressed air from the space ofa large final-volume, and consequently it takes a long time to bring the circuit breaker to its circuit making position.

The circuit breaker operating devices of the prior art are constructed such that the operating cylinder in which the operating position is mounted and the air introducing valve means for introducing compressed air into the operating cylinder are interconnected by an air pipe, and the air introducing valve means comprises a plurality of amplifier valves which successively amplify an operation signal, and an air introducing valve which is actuated by the amplifier operation signal and supplies compressed air to the operating cylinder. Some disadvantages are associated with this arrangement. A considerably long time elapses after the operation signal is received and before the air introduction valve is actuated. It takes a considerably long time to move the operating piston in a direction where the circuit breaker is brought to its circuit breaking position by opening the air introducing valve to introduce compressed air into the operating cylinder, because of pressure loss in the air pipe and other factors. Thus the devices of the prior art take a considerably long time to bring the circuit breaker to its circuit breaking position and have hitherto been incapable of operating the circuit breaker at high speed.

SUMMARY OF THE INVENTION An object of the invention is to provide a circuit breaker operating device which is capable of operating at high speed a circuit breaker which is under a high load and which has a large contact parting distance.

Another object of the invention is to provide a circuit breaker operating device which is simpler in construction than similar devices of the prior art.

Another object of the invention is to provide a circuit breaker operating device which is capable of bringing the circuit breaker to a circuit making position at high speed immediately after the circuit breaker is brought to a circuit breaking position to interrupt a current.

Another object of the invention is to provide a circuit breaker operating device in which the air introducing valve means adapted to supply the operating piston with an operating medium can be actuated in a short time upon receipt of an operating signal.

A further object of the invention is to provide a circuit breaker operating device in which an operating medium can be supplied to the operating piston efficiently after the air introducing valve means adapted to introduce the operating medium into the operating cylinder is brought to an open position.

According to the invention, there is provided a circuit breaker operating device comprising an operating piston disposed at one end of an operating rod for operating a circuit breaker, a cylinder for guiding the operating piston in its sliding movement, a circuit making means adapted to provide a force to cause the operating rod to bring the circuit breaker to a circuit making position. a hook means adapted to be brought into engagemcnt with the operating rod to maintain the circuit breaker in a circuit breaking position when instructions to break the circuit are given and released from engagement with the operating rod when instructions to make the circuit are given, a fluid introducing valve means for supplying an operating medium to the operating piston to move the same in a circuit breaking direction when instructions to break the circuit are given. and communication ports for discharging therethrough from the cylinder to a lower pressure section the operating medium acting on the operating piston at least at the terminating stages of the circuit breaking opera tion. By this arrangement, the device according to the invention is capable of bringing the circuit breaker to its circuit making position at high speed. The air introducing valve means is adapted to supply the operating piston with the operating medium and comprises an air introducing valve disposed in the vicinity of the operating piston and moving toward the operating piston when the valve is opened, a piston connected to the air introducing valve and normally urged by the operating medium to move in a direction where the air introducing valve is closed, and another piston receiving a sup ply of the operating medium through a change-over valve to open the air introducing valve. By this arrangement, the device according to the invention is capable of operating in a short time upon receipt of a operation signal immediately to supply the operating medium to the operating piston whereby the operating piston can be actuated to bring the circuit breaker to its circuit breaking position at high speed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are sectional views of the circuit breaker operating device comprising one embodiment of the invention. FIG. 1 showing the device in a position which corresponds to the closed or circuit making position of the circuit breaker and FIG. 2 showing the device in a position which corresponds to the open or circuit breaking position thereof;

FIG. 3 is a sectional view of the circuit breaker operative device comprising another embodiment of the invention;

FIG. 4 is a sectional view ofthe circuit breaker operating device comprising still another embodiment of the invention; and

FIG. 5 is a sectional view taken along the line V-V of FIG. 4.

DESCRIPTION OF EMBODIMENTS FIG. 1 and FIG. 2 show one embodiment of the invention. The circuit breaker operating device shown in FIG. 1 is in a position which corresponds to the closed or circuit making position of the circuit breaker while the circuit breaker operating device shown in FIG. 2 is in a position which corresponds to the open or circuit breaking position thereof. In the figures. an operating rod 1 is connected at one end to a movable contact of a circuit breaker (not shown) and at the other end to a operating piston 4 through a pivotal lever 2 and a hinge 3. The operating piston 4 is slidably arranged in an operating cylinder 23 mounted in an operation box 5 with a clearance being interposed between walls of the cylinder 23 and the box 5.

A circuit making spring 6 is connected to the operating rod I as a means for providing a force for causing the operating rod to bring the circuit breaker to a circuit making position. and maintains the operating rod 1 and the operating piston 4 in positions in FIG. 1 through the pivotal lever 2 pivoted at 7. A portion 5a of the operation box 5 constitutes a valve box of a fluid introducing valve means 8 which is maintained in communication with a storage tank I2 lor compressed air serving as an operating medium through a fluid supply pipe 9 on one hand and a three-way electromagnetic valve [0 and a fluid supply pipe II on the other.

The fluid introducing valve means 8 comprises a fluid introducing valve 8a and a piston 8/) which are mechanically connected to each other and exposed, at opposing surfaces thereof, to the compressed air supplied through the fluid supply pipe 9, so that the valve 8a and the piston 8b are brought into engagement with valve seats I3 and I4 respectively by virtue of the difference between the pressure applied to the valve 8a and the pressure applied to the piston 8b. This precludes flow of compressed air into the cylinder 23. The fluid introducing valve means 8 further comprises a piston disposed at the lowermost end of the valve means which in under the influence ofa compression spring 15 to aid in maintaining the fluid introducing valve 8a in its closed position.

Another portion 511 of the operation box 5 receives therein an exhaust valve 16 for sliding motion. The exhaust valve 16 is connected. through a hinge 17, to a hook lever 19 pivoted at 18 and maintained in engagement with the pivotal lever 2. The exhaust valve 16, which is under the influence of a compression spring 20, is maintained in a closed position as shown in FIG. I because the hook lever 19 is positioned against a roller 12 attached to the pivotal lever 2 and prevented from moving in pivotal motion.

An electromagnetic hook 22, which is adapted to come into engagement with the hook lever [9 to regu late the movement thereof. will subsequently be described in detail. The operation of the circuit breaker operating device constructed as aforesaid to bring the circuit breaker to its circuit breaking position will be described first. A solenoid [011 for the three-way electromagnetic valve 10 is energized upon receipt of instructions to break the circuit and actuates the valve 10 to allow a space A to communicate with the fluid supply pipe Il. This permits compressed air to act on the piston 80 of the fluid introducing valve means 8 to move the valve means 8 upwardly. This upward movement of the valve means 8 is interrupted after the valve means 8 has covered a small distance before the fluid introducing valve 80 is brought into engagement with the operating piston 4. However. since the compressed air in the storage tank 12 flows, together with the compressed air already fllled in a space B, at high speed into a space C through the fluid supply pipe 9 and space B because the fluid introducing valve 80 is released from engagement with the valve seat 13, the operating piston 4 moves upwardly against the biasing force of the circuit making spring 6. Thus the upward movement of the fluid introducing valve 8a is soon resumed and continues till the piston 8b is brought into engagement with a stopper 24 disposed in the operation box 5. The upward movement of the fluid introducing valve means 8 taking place in slaved relation to the movement of the operating piston is aided by the provision of a vent hole 4a formed in the operating piston 4 which permits atmospheric pressure to act on the upper surface of the fluid introducing valve 8a.

By virtue of this arrangement, the space C is scaled by the operating piston 4, cylinder 23 and fluid introducing valve 8a, so that the compressed air effectively acts on the operating piston in the initial stages. As the operating piston 4 moves upwardly, the space C is brought into communication with a space D through communication ports 23a formed in an intermediate portion ofa side wall ofthe cylinder 23. Since the space D is sealed airtight by the exhaust valve 16, no compressed air is allowed to be vented to atmosphere.

Upward movement of the operating piston 4 results in the roller 21 on the piston lever 2 moving upwardly along the hook lever 19 and passes by a first hook 190. Since the hook lever 19 is urged to move coutner clockwise in pivotal motion by the pressure applied by the compressed air to the exhaust pipe 16 and the biasing force of the compression spring 20, a pin 3a attached to the hinge 3 is brought into engagement with the first hook 19a as shown in FIG. 2. At this time, the electromagnetic hook 22 is brought into engagement with a second hook 19b of the hook lever 19 and the exhaust valve 16 moves upwardly, so that the space D and hence the space C are allowed to communicate with atmosphere, thereby venting compressed air into atmosphere from the spaces C and D. Prior to this, the solenoid a is de-energized and the three-way electromagnetic valve 10 is restored to its position shown in FIG. 2 to allow the space A to communicate with atmosphere, thereby venting compressed air into atmosphere from the space A. Removal of compressed air from the space A permits the fluid introducing valve means 8 to be restored to its position shown in FIG. 2 by the biasing fore of the compression spring 15, with the result that the fluid introducing valve 8a is brought into airtight sealing engagement with the valve seat 13.

Even after the compressed air in the spaces C and D is removed therefrom, the operating rod 1 is maintained, by the static balance existing between the pivot 7, pivotal lever 2, pin 3a, first hook 19a, hook lever 19, pivot 18, second hook 19b and electromagnetic hook 22, in a position shown in FIG. 2 in which it maintains the circuit breaker in its circuit breaking position.

The operation of the device according to the invention to bring the circuit breaker to its circuit making position will now be described. Upon receipt of instruc tions to bring the circuit breaker to its circuit making position, a solenoid 22a for the electromagnetic book 22 of the device in a state shown in FIG. 2 is energized so as to release the electromagnetic hook 22 from engagement with the second hook 19b of the hook lever 19. This disturbes the aforementioned static balance of the parts and the pin 3a is released from engagement with the first hook 190 of the hook lever 19, with the result that the operating rod 1 and operating piston 4 are moved downwardly by the biasing force of the circuit making spring 6. The roller 21 on the pivotal lever 2 moves downwardly again along the hook lever 19 as the pivotal lever 2 moves clockwise about the pivot 7. At the same time, the hook lever [9 moves clockwise about the pivot 18 as the electromagnetic book 22 is released from engagement with the second hook 1% as aforesaid. so that the exhaust valve 16 moves downwardly and closes the space D.

When the operating piston 4 moves downwardly. the space C is compressed and the pressure therein slightly rises. However, air is vented through the communication ports 230 formed in the side wall of the cylinder 23 and the vent hole 4a formed in the operating piston 4 and the rise in pressure is not so high as to interrupt the downward movement of the operating piston 4. Thus the operating piston 4 and operating rod 1 move downwardly to the positions shown in FIG. I which correspond to the circuit making position of the circuit breaker.

The device constructed as aforesaid is capable of bringing the circuit breaker to its circuit making position at high speed. Since the compressed air in the spaces C and D is completely vented to atmosphere through the exhaust pipe 16 before the circuit breaker is actually brought to its circuit making position, the need to discharge compressed air in returning the operating piston 4 to its original position is eliminated. Also. a reaction to the downward movement of the operating piston 4 which might otherwise occur owing to a rise in pressure in the cylinder and act as a deterrent force can be minimized. The vent hole 4a formed in the operating piston 4 to preclude a rise in pressure in the space C is closed by the fluid introducing valve of the fluid introducing valve means 8 for a proper time interval when the device operates to bring the circuit breaker to its circuit breaking position. Thus the provision of the vent hole 4a not only does not interfere with the high speed operation of the operating pisotn 4, but also ensures that the fluid introducing valve 8a moves in slaved relation to the operating piston 4 for a proper time interval.

The exhaust valve 16 is maintained in the closed position by the hook lever 19 and prevented from opening when the circuit breaker is in its circuit making position. It is only when the circuit breaker is brought to the circuit breaking position and the pin 30 is positively engaged by the hook lever 19 that the exhaust valve I6 is opened. These parts are intimately related to one another and operate in sequence both chronologically and spatially as if they formed a single mechanism, so that the operating device according to the invention is highly reliable in performance.

The cirueit breaker is mechanically maintained in the circuit breaking position by the hook lever 19 and electromagnetic hook 22. This eliminates the need to use an additional means for detecting a reduction in the pressure of compressed air and lock the circuit breaker in the circuit breaking position which has been used with conventional circuit breaker operating devices.

In the present invention. means for controlling the fluid introducing valve means 8 and exhaust valve 16 are arranged independently of each other in the vicinity of the operating piston. This permits the circuit breaker operating device to be used with various types of circuit breakers differing from one another in the load applied thereto and the contact parting distance by interchanging various parts of the control means. Besides, the influences exerted by the operation of various means on one another are so small and negligible that the circuit breaker operating device is fit for continuous high speed operation.

FIG. 3 shows another embodiment of the invention. In FIG. 3, like reference characters designate parts similar to those shown in FIG. I and FIG. 2. The embodiment shown in FIG. 3 is distinguished from the embodiment shown in FIG. I and FIG. 2 by the fact that the control valve 16 and the parts associated therewith disclosed in the latter are eliminated in the former. with portion ot'the side wall of the operation box 5 being exposed to atmosphere. A compression spring is connected to the hook lever 19 so as to force the hook lever 19 tightly against the pivotal lever 2 by its biasing force.

In operation. the fluid introducing valve 8a is released from engagement with the valve seat 13 upon receipt of instructions to bring the circuit breaker to its circuit breaking position. This permits the compressed air in the storage tank 12 to flow through the fluid supply pipe 9 and space 8. together with the compressed air already in the space B. into the space C. so as to thereby urge the operation piston 4 to move upwardly against the biasing force of the circuit making spring 6. At this time, the fluid introducting valve 8a is brought into engagement with the operating piston 4 and closes the vent hole formed in the operating piston 4, so that the former moves in slaved relation to the latter. In the initial stages of operation the space C is a sealed space closed by the operating piston 4, cylinder 23 and air introducing valve 8a, so that the high speed upward movement of the piston 4 is not interrupted in any way.

As the operating piston 4 moves upwardly, the space C is allowed to communicate with atmospheric through the plurality of communication ports 23a formed in the middle portion of the side wall of the cylinder 23. By suitably selecting the number or the dimension of the air of the communication ports 23a in the side wall of the cylinder 23, it is possible to permit the operating cylinder to move upwardly at high speed without any interruption. The advantage offered by the provision of the communication ports 23a can be increased if the number of the communication ports is increased or the sectional area of each port is increased in the upper portion of the side wall of the cylinder in FIG. 3.

As the operating piston 4 further moves upwardly, the roller 21 attached to the pivotal lever 2 moves upwardly along the hook lever 19 and passes by the first hook 19a. Since the hook lever 19 is urged to move counter clockwise about the pivot 18 by the biasing force of the compression spring 30, the pin 3a is brought into engagement with the first hook 19a. At this time, the electromagnetic hook 22 is brought into engagement with the second hook 19b of the hook lever 19. The fluid introducing valve 8a is closed as soon as the electromagnetic hook 22 is brought into engagement with the second hook 19b. and the compressed air in the space C is vented to atmosphere through the communication ports 23a. The circuit breaker is maintained in its circuit breaking position by the engagement of the pin 3a with the first hook 19a and the engagement of the electromagnetic hook 22 with the second hook [9b.

The embodiment shown in FIG. 3 operates substantially similarly to the embodiment shown in FIG. I and FIG. 2 to bring the circuit breaker to its circuit making position from its circuit breaking position. The operation is started by releasing the electromagnetic hook from engagement with the second hook 19b. This permits the operating piton 4 to move smoothly because the compressed air in the space C has been completely vented. A rise in the pressure of air in the space C which might otherwise be caused by the downward movement of the operating piston 4 is eliminated by the venting of air from the space C through the communication ports 23a formed in the side wall of the cylinder 23 and the vent hole 4a formed in the operating piston. so that the downward movement of the operating piston 4 takes place smoothly without any interruption. Th us the circuit breaker is brought to its circuit making position.

The embodiment of the invention constructed as shown in FIG. 3 is simpler in construction than the embodiment shown in FIG. I and FIG. 2 and yet the former is no less reliable than the latter.

In this embodiment. the compressed air in the cylinder 23 is vented to atmosphere through the communication ports 230 formed in the middle portion of the side wall of the cylinder 23. It is to be understood that the invention is not limited to this arrangement and that small ports may be formed in the operating piston 4 in place of the communication ports 23a. such small ports being closed by the air introducing valve in the initial stages of circuit breaking operation and opened thereafter to vent the compressed air therethrough, whereby similar results can be achieved.

FIG. 4 shows still another embodiment of the invention in which an operating rod 41 is connected at one end to a circuit breaking portion of a circuit breaker (not shown) and at the other end to an operating piston 42 slidably disposed in an operating cylinder 43. A fluid introducing valve 44 which is adapted to supply compressed air into the operating piston 42 is disposed in the vicinity of the operating piston 42 and adapted to cooperate with a valve seat 45 to prevent the flow of compressed air into the operating cylinder when the valve is in engagement with the valve seat. Connected directly to a bottom wall 430 of the operating cylinder 43 is a fluid chamber casing 47 which houses therein a fluid chamber 46 filled with compressed air at all times.

The casing 47 is formed therein with a fluid supply port 48 which is connected to a fluid tank 40 through a connecting pipe 39. A partition wall 49 is arranged eccentrically within the casing 47 so that it is biased toward a side of the casing 47 which is opposite to a side at which the fluid supply port 48 is disposed. The compressed air supplied from the fluid tank 40 to the fluid chamber 46 is supplied to the air introducing valve 46 through the interior of the partition wall 49 as subsequently described.

The fluid introducing valve 44 is connected through a connecting rod 50 to a control piston 51 disposed in the partition wall 49 and at an end of the fluid chamber 46 opposite to an end at which the air introducing valve 44 is disposed. The compressed air in the fluid chamber 46 acts on the control piston 51 and urges the same to move such as to bring the fluid introducing valve 44 to closed position. The control piston 51 cooperates with a compression spring 52 automatically to keep the air introducing valve 44 in its closed position.

Disposed below the control piston SI is an auxiliary fluid chamber 54 which is maintained in communication through a pilot valve 53 with the fluid introducing chamber 46 filled with compressed air and which is maintained in communication with atmosphere through a change-over valve 55. Arranged within the partition wall 49 is a guide means 56 which guides the connecting rod 50 and moves the compressed air within the partition wall 49 toward the fluid introducing valve 44.

The pilot valve 53 and change-over valve 55 are housed in a pilot valve casing 57. directly connected to the fluid chamber casing 47, and arranged such that they are moved in a direction at right angles to the direction of movement of the fluid introducing valve 44 by means ofa push-rod 58 connected to an electromagnetic operating means (not shown). By directly connecting the bottom wall 43a of the operating cylinder 43, the fluid chamber casing 47 and the pilot valve casing 57 to one another as aforementioned, it is possible to obtain an overall compact size in a circuit breaker operating device. By arranging the pilot valve 53 and the changeover valve 55 to move in a direction at right angles to the direction of movement of the fluid introducing valve 44, it is possible to further reduce the overall size of the circuit breaker operating device.

FIG. is a sectional view taken along the line VV of FIG. 4 and shows the arrangement of the partition wall 49 which is cylindrical in shape and formed therein with a plurality of communication ports 61. As aforementioned, the partiiton wall 49 is disposed eccentrically within the fluid chamber 46 such that the clearance between the partition wall 49 and the side of the fluid chamber 46 at which the fluid supply port 48 is formed is greaterjhan the clearance between the partition wall 49 and the opposite side of the fluid chamber 46. By this arrangement, it is possible to supply each communication port 61 with a substantially equal volume of compressed air and introduce compressed air efficiently into the interior of the partition wall 49 through the communication ports 61. i

The operation of the embodiment constructed as aforementioned will be described. Upon receipt of im structions to bring the circuit breaker to its circuit breaking position, the electromagnetic operating means (not shown) moves the push-rod 58 rightwardly in FIG. 4 to close the change-over valve 55 and open the pilot valve 53, so as to fill the auxiliary fluid chamber 54 with compressed air. As a result, the control piston 5] is moved upwardly in FIG. 4 by the compressed air introduced into the auxiliary fluid chamber 54 and moves the fluid introducing valve 44 upwardly away from the valve seat 45 to its open position. Since the fluid introducing valve 44 is exposed at its back to the compressed air filled in the fluid chamber 46 at all times, the compressed air in the fluid chamber 46 is immediately introduced through the fluid introducing valve 44 into the operating cylinder 43 where it acts on the operating piston 42 and moves the same upwardly at high speed. The fluid introducing valve 44 in the open position moves further upwardly in slaved relation to the operating piston 42 moving upwardly at high speed so as to close a vent hole 59 formed in the operating piston and help the compressed air act effectively on the operating piston. The upward movement of the air introducing valve 44 taking place in slaved relation to the operating piston 42 is interrupted by the control valve 5] abutting against an offset portion 560 of the guide means 56.

The operating piston 42 is further moved upwardly by the compressed air introduced into the operating cylinder 43. However, a portion of the compressed air introduced into the operating cylinder 43 is vented through the vent hole 59 after the upward movement of the control piston 51 is precluded, so that the pressure of the compressed air acting on the operating piston is reduced. At this time, the push-rod 58 is moved rightwardly by the electromagnetic operating means (not shown) to close the pilot 53 and open the changeover valve 55, thereby venting compressed air from the auxiliary fluid chamber 54. Thus. the fluid introducing valve 44 is automatically brought to its closed position by the downward movement. of the control piston 51 caused by the pressure of the compressed air acting on its back and the biasing force of the compression spring 52.

When the operating pistion 42 reaches the end of its upward movement in the operating cylinder 43, the op erating rod 41 is engaged by an engaging means (not shown), so that the circuit breaker is maintained in its circuit breaking position. The compressed air in the operating cylinder 43 is vented therefrom through an exhaust port formed in a side-wall of the operating cylinder 43and the vent hole 59 formed in the operating piston 42.

The operation of the device to bring the circuit breaker to its curcuit making position'will be described. The operating piston 42 is moveddownwardly in FIG. 4 from its upper position through the operating rod 4] by a compression spring or other means for bringing the circuit breaker to its circuit making position. Since there is no compressed air in the operating cylincer 43, there is no resistance offered to the downward movement of the operating piston 42, so that the circuit breaker can readily be moved to its circuit making position. The air in the operating cylinder 43 is compressed by the downward movement of the operating cylinder 42 at the terminating stages of the operation to bring the circuit breaker to its circuit making position.

However, air is vented through the vent hole 59 in the operating piston 42, so that a rise in pressure is precluded and the operating piston 42 can move at high speed. Thus it is possible to bring the circuit breaker to its circuit making position at high speed.

In each embodiment, compressed air has been shown and described as being used as an operating medium. It is to be understood that the invention is not limited to this specific form of operating medium and that SF gas or other gas filled in the circuit breaking portion as an insulating medium or liquid may be used as an operating medium.

We claim:

I. A circuit breaker operating device comprising an operating piston connected to one end of a pivotal lever attached to an operating rod which operates a circuit breaker, cylinder means for guiding said operating piston to move in sliding motion, circuit making means providing a force which causes said operating rod to bring the circuit breaker to a circuit making position, hook means removably engaging said pivotal lever attached to said operating rod and maintaining the circuit breaker in a circuit breaking position when instructions to break the circuit are given. said hook means being released from engagement with said pivotal lever when instructions to make the circuit are given, fluid introducing valve means having a valve seat formed on an end plate of said cylinder means and a fluid introducing valve for supplying an operating medium to said operating piston to move the same in a circuit breaking direction when instructions to break the circuit are given, and communication ports formed in a side wall of said cylinder means for discharging from said cylinder means to a lower pressure section the operating me dium acting on said operating piston at least at the ter- 1 l minating stages of the circuit breaking operation when said operating piston is moved to open said communication ports.

2. A circuit breaker operating device as set forth in claim 1, wherein said operating piston is formed therein with a small hole, said small hole being closed by said fluid introducing valve means at least at the initial stages of the circuit breaking operation and venting therethrough the operating medium from said cylinder means when the circuit breaker is brought to its circuit making position.

3. A circuit breaker operating device as set forth in claim 1, wherein said fluid introducing valve supplies said operating medium to said operating piston dis posed in the proximity of said operating piston and is moved toward said operating piston when brought to an open position; and said fluid introducing valve means also has a second piston connected to said fluid introducing valve and normally exposed to said operating medium such that said fluid introducing valve is biased by the pressure of operating medium to move to a closed position, and a third piston receiving a supply of operating medium through a change-over valve and which moves said fluid introducing valve to its open po' sition.

4. A circuit breaker operating device as set forth in claim 3, wherein said fluid introducing valve and said second piston are disposed in spaced juxtaposed relationship, with the space between them being filled with the operating medium at all times.

5. A circuit breaker operating device as set forth in claim I, wherein said fluid introducing valve supplies said operating medium to said operating piston disposed in the proximity of said operating piston and moves toward said operating piston when brought to an open position; and said fluid introducing valve means also has a second piston connected to said fluid introducing valve, said second piston normally exposed to said operating medium on one surface thereof such that said fluid introducing valve is biased by the pressure of said operating medium to move to a closed position and receives a supply of operating medium through a change-over valve to the other surface thereof such that said fluid introducing valve is biased by the pressure of said operating medium to move to a closed position.

6. A circuit breaker operating device as set forth in claim 1, in which said fluid introducing valve supplies said operating medium to said ope rating piston and said fluid introducing valve means further has a fluid chamber formed on a side of said fluid introducing valve to which said operating medium is supplied and filled with said operating medium at all times. a fluid supply port formed in a portion of a side wall of said fluid chamber for supplying therethrough said operating medium to said fluid chamber. said side wall of said fluid chamber being cylindrical in shape. and a cylindrical partition wall arranged within said fluid chamber such that the interior of said partition wall communicates with said cylinder through said fluid introducing valve when the latter is open, said partition wall being formed therein with a plurality of communication ports and eccentrically disposed in said fluid chamber such that the clearance between said partition wall and a side of the side wall of said fluid chamber at which said fluid supply port is formed is greater than the clearance between said partition wall and the opposite side of said fluid chamber.

7. A circuit breaker operating device as set forth in claim I, further comprising a casing arranged to house therein said cylinder means with a small clearance being disposed between said casing and said cylinder means. and an exhaust valve means mechanically connected to said hook means and adapted to vent the for venting said operating medium ther'ethrough from said casing when said hook means is brought into engagement with the operating rod to keep the circuit breaker in the circuit breaking position. 

1. A circuit breaker operating device comprising an operating piston connected to one end of a pivotal lever attached to an operating rod which operates a circuit breaker, cylinder means for guiding said operating piston to move in sliding motion, circuit making means providing a force which causes said operating rod to bring the circuit breaker to a circuit making position, hook means removably engaging said pivotal lever attached to said operating rod and maintaining the circuit breaker in a circuit breaking position when instructions to break the circuit are given, said hook means being released from engagement with said pivotal lever when instructions to make the circuit are given, fluid introducing valve means having a valve seat formed on an end plate of said cylinder means and a fluid introducing valve for supplying an operating medium to said operating piston to move the same in a circuit breaking direction when instructions to break the circuit are given, and communication ports formed in a side wall of said cylinder means for discharging from said cylinder means to a lower pressure section the operating medium acting on said operating piston at least at the terminating stages of the circuit breaking operation when said operating piston is moved to open said communication ports.
 2. A circuit breaker operating device as set forth in claim 1, wherein said operating piston is formed therein with a small hole, said small hole being closed by said fluid introducing valve means at least at the initial stages of the circuit breaking operation and venting therethrough the operating medium from said cylinder means when the circuit breaker is brought to its circuit making position.
 3. A circuit breaker operating device as set forth in claim 1, wherein said fluid introducing valve supplies said operating medium to said operating piston disposed in the proximity of said operating piston and is moved toward said operating piston when brought to an open position; and said fluid introducing valve means also has a second piston connected to said fluid introducing valve and normally exposed to said operating medium such that said fluid introducing valve is biased by the pressure of operating medium to move to a closed position, and a third piston receiving a supply of operating medium through a change-over valve and which moves said fluid introducing valve to its open position.
 4. A circuit breaker operating device as set forth in claim 3, wherein said fluid introducing valve and said second piston are disposed in spaced juxtaposed relationship, with the space between them being filled with the operating medium at all times.
 5. A circuit breaker operating device as set forth in claim 1, wherein said fluid introducing valve supplies said operating medium to said operating piston disposed in the proximity of said operating piston and moves toward said operating piston when brought to an open position; and said fluid introducing valve means also has a second piston connected to said fluid introducing valve, said second piston normally exposed to said operating medium on one surface thereof such that said fluid introducing valve is biased by the pressure of said operating medium to move to a closed position and receives a supply of operating medium through a change-over valve to the other surface thereof such that said fluid introducing valve is biased by the pressure of said operating medium to move to a closed position.
 6. A circuit breaker operating device as set forth in claim 1, in which said fluid introducing valve supplies said operating medium to said operating piston and said fluid introducing valve means further has a fluid chamber formed on a side of said fluid introducing valve to which said operating medium is supplied and filled with said operating medium at all times, a fluid supply port formed in a portion of a side waLl of said fluid chamber for supplying therethrough said operating medium to said fluid chamber, said side wall of said fluid chamber being cylindrical in shape, and a cylindrical partition wall arranged within said fluid chamber such that the interior of said partition wall communicates with said cylinder through said fluid introducing valve when the latter is open, said partition wall being formed therein with a plurality of communication ports and eccentrically disposed in said fluid chamber such that the clearance between said partition wall and a side of the side wall of said fluid chamber at which said fluid supply port is formed is greater than the clearance between said partition wall and the opposite side of said fluid chamber.
 7. A circuit breaker operating device as set forth in claim 1, further comprising a casing arranged to house therein said cylinder means with a small clearance being disposed between said casing and said cylinder means, and an exhaust valve means mechanically connected to said hook means and adapted to vent the for venting said operating medium therethrough from said casing when said hook means is brought into engagement with the operating rod to keep the circuit breaker in the circuit breaking position. 